Provides a classification of the systems, the definition of minimum requirements and the values of the reference quantities during operation. It is applied to aeraulic systems designed for people’s comfort and installed in closed buildings, except for:

• air-conditioning systems used in winter for buildings used for industrial activities or craftsmanship (for which UNI 8852 is applied);
• systems designed for other purposes, for instance to preserve perishable products and/or to create suitable conditions for special industrial manufacturing processes (process systems);
• systems only used for heating in winter and cooling in summer with no mechanical introduction of air from outdoors.

The standard is currently under revision and as for the classification of the indoor and outdoor air quality, the concepts of the EN 13779 standard have been implemented and the classification is essentially the same:

The standard is applied to high and very high efficiency air filters with ultra-low penetration (EPA, HEPA and ULPA) used in the field of ventilation and air-conditioning, as well as in technological processes such as clean-room technology or the pharmaceutical industry. It establishes a procedure to determine efficiency based on a method that counts particles with a test liquid aerosol (or alternatively a solid one) and can classify these filters in a normalised way depending on their efficiency.
The following table shows the various classes for high efficiency filters in accordance with EN 1822:

Part 1: Classification of air cleanliness.

The ISO 14644-1 standard covers the classification of air cleanliness in clean rooms and associated controlled environments. Classification in accordance with this standard is carried out exclusively based on concentration of suspended particles. Furthermore, the particles considered for the purposes of classification based on this standard are those with sizes ranging from 0.1 micron to 5 micron.

Design, installation, start-up, qualification, management and maintenance
The standard provides directions for the design, installation, start-up, performance control, acceptance, management of systems and components that contribute to controlling contamination in the facilities and maintaining pre-set temperature and humidity conditions in units specifically intended to carry out surgery, called surgery units.
The standard is applied to new systems and refurbishments concerning buildings and/or systems in surgery units and provides the minimum requirements to verify the conditions of use of existing ones.
Below are the values recommended by UNI 11425 for environmental parameters and some quantities associated with them.
To reach the designed air purity class in the various rooms, the standard also identifies the minimum efficiency level for the air filters:

The International Organization for Standardization (ISO) created a new global standard, ISO16890, which defines the classification and testing procedures for air filters employed in general ventilation systems. In particular, ISO16890 refers to the air filtering element taking into account particles with a size comprised between 0,3 μm e 10 μm (see table).
The new standard, which will enter into force in August 2018, replaced the current European Standard EN 779 and the ASHRAE52.2, employed in the USA, with the aim of creating a unique global standard divided into 4 classes, based on the filter performance in connection with three different particle fractions, with a more targeted percentage that indicates the filter efficiency.
The main differences between Standard ISO16890 and current ones are the tests, which will become more stringent, with a consequent IAQ increase, and the fact that the finer dust classified – PM1 – is also the most dangerous for human health. High-efficiency filters will help improving the quality of the air we breathe.

Classification